1. Field of the Invention
The present invention generally relates to lithium polymer batteries.
2. Description of the Related Art
Typically, unlike primary batteries that are not rechargeable, secondary batteries are rechargeable. Secondary batteries are used as energy sources for small mobile display devices, such as a smart phone, a digital camera, a video camera, a camcorder, a portable information terminal device, a tablet personal computer, or a super-slim notebook computer, or middle- and large-sized devices, such as an electric vehicle, a hybrid electric vehicle, an electric bicycle, or an uninterruptible power supply (UPS).
Small mobile display devices use a small number of battery cells. Also, middle- and large-sized devices require high power output and large capacities, and thus, they use a battery pack in which a plurality of battery cells are electrically connected to each other.
The battery cells are connected in series or parallel and are placed in a battery unit. A plurality of the battery units are connected to each other to form a battery module. A plurality of the battery modules are connected to each other to form a battery pack to provide high power output and capacitance.
The above information disclosed in this Related Art section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.